Easy Question...

Hi,
   I'm trying to pass a filename to WinExec. The problem is
that I have to build the name using info from the user.
I have done this:
var
   AppName : String;
   FileName: String;
   ExecuteLin : String;
   ExecuteLine : PChar;
begin
   AppName := 'Latex ';
   FileName := Edit1.Text;
   ExecuteLin := AppName + FileName;
   StrPCopy(ExecuteLine, ExecuteLin);
   WinExec(ExecuteLine, SW_SHOWMAXIMISED);
end;

When I try to run it I get a General Protection Fault, with
the StrPCopy line highlighted. Anyone know what seems to be
the problem?
Thanks...

LVL 1
NikWhitAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

julio011597Commented:
The problem is that PChar is a Pointer to a Null-Terminated string, so it needs to be initialized; since you didn't allocate memory for it, your StrPCopy() call generates that GPF error.

Anyway, solving the problem is trivial, due to Delphi assignment compatibility; just typecast your "ExecuteLin" to PChar:

--//--
var
  AppName: String;
  FileName: String;
  ExecuteLin : String;
begin
  AppName := 'Latex ';
  FileName := Edit1.Text;
  ExecuteLin := AppName + FileName;
  WinExec(PChar(ExecuteLin), SW_SHOWMAXIMISED);
end;
--//--

BTW, say you want to keep the "ExecuteLine" stuff for some reason; the easier way to make your code work is:

ExecuteLine: array[0..128] of Char; { now space is allocated }

Technically, array of Char and PChar are not the same, but this could be matter for another hard question :)
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
NikWhitAuthor Commented:
I've just tried your suggestion, and on compilation, it reports
that it's an invalid cast. Any ideas?
Thanks...
Nik
0
julio011597Commented:
Is it Delphi1?

Sorry, try my second suggestion; declare ExecuteLine as:

ExecuteLine: array[0..128] of Char;

Let me know...
0
NikWhitAuthor Commented:
julio,
seems to work fine! I guess there must be a difference between
my version and yours. Using the char array is no problem for
my app, though. Thanks for your help...
Nik

0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Delphi

From novice to tech pro — start learning today.